Fine root decomposition and nutrient release in Toona sinensis plantation under the reconstruction mode of low-efficiency cypress forest gaps北大核心CSCD

Fine root decomposition is an important way in which nutrients are returned to plantation soil; thus, further study of this process will be helpful for understanding material cycling in forest ecosystems. We investigated a Toona sinensis plantation in the central Sichuan hilly region using litter bags containing T. sinensis fine roots to evaluate the dynamics of fine root decomposition and nutrient release for one year in forest gaps of 50 m2 (L1), 100 m2 (L2), and 150 m2 (L3). The results showed that T. sinensis fine root decomposition was fastest in the first 90 days. As time passed, the decomposition rate slowed. One year later, the residue rate was 75.44%, 73.92%, and 72.07%, respectively. The fine root decomposition rate of L3 was greater than that of L2, which was greater than that of L1. During fine root decomposition, the dynamics of the fine root nutrient concentrations changed. C, P, and K concentrations of the fine roots declined in forest gaps, while N, Ca, and Mg concentrations increased overall in the fine roots. In conclusion, forest gaps had effects on the fine root decomposition and nutrient release of T. sinensis, and different sized forest gaps produced different results. © 2018 Science Press. All rights reserved.     

Soil physicochemical properties of Pinus tabuliformis plantations of different ages in Yanqing,Beijing北大核心CSCD

Soil physicochemical properties are important parameters to characterize soil quality. To evaluate the effects of different stand ages from young to mature on the soil physicochemical properties of Pinus tabulaeformis plantations, four different aged P. tabulaeformis plantations (14, 28, 36, and 51-year old) were investigated in Yanqing district, Beijing, China. Soil samples were collected at depths of 0-10, 10-20, and 20-30 cm, to analyze the effect of soil depth on soil physicochemical indexes. With increasing soil depth, the soil moisture content, water holding capacity, and porosity decreased gradually, but pH value increased. There was no significant difference in soil bulk density (BD) between different soil depths. Organic matter (OM), nitrogen (N), phosphorus (P), and potassium (K) content also decreased gradually with increasing soil depth, but there was no uniform change in electrical conductivity (EC). With the growth and development of P. tabulaeformis plantations, the soil moisture content, water holding capacity, and porosity of the same depth increased gradually, but pH value decreased. The difference in BD between different ages was not significant. The OM, N, and P content showed an increasing trend with increasing stand age. The K content in 14 a and 28 a plantations was significantly higher than that in 36 a and 51 a plantations. EC was the highest in 51 a plantations. The correlation analysis showed that there was a significant negative correlation between BD and water characteristics, porosity. There was a significant positive correlation between OM and N, P. The negative correlation between OM and pH reached a significant level at P < 0.01. OM was negatively correlated with BD, total potassium (TK, P < 0.05) and available potassium (AK, P > 0.05). Therefore, the soil physicochemical properties of P. tabulaeformis plantations improved with increasing stand age. Our results provide a theoretical basis for the management of P. tabulaeformis plantations in Beijing, such as thinning, fertilization management, and mixed forest forestation. © 2018 Science Press. All rights reserved.     

Thermodynamic estimation of minor element distribution between immiscible liquids in Fe-Cu-based metal phase generated in melting treatment of municipal solid wastes

Waste electrical and electronic equipment (WEEE) has become an important target in managing material cycles from the viewpoint of not only waste management and control of environmental pollution but also resource conservation. This study investigated the distribution tendency of trace elements in municipal solid waste (MSW) or incinerator ash, including valuable non-ferrous metals (Ni, Co, Cr, Mn, Mo, Ti, V, W, Zr), precious group metals (PGMs) originated from WEEE (Ag, Au, Pd, Pt), and others (Al, B, Pb, Si), between Fe-rich and Cu-rich metal phases by means of simple thermodynamic calculations. Most of the typical alloying elements for steel (Co, Cr, Mo, Nb, Ni, Si, Ti, V, and W) and Rh were preferentially distributed into the Fe-rich phase. PGMs, such as Au, Ag, and Pd, were enriched in the Cu-rich phase, whereas Pt was almost equally distributed into both phases. Since the primary metallurgical processing of Cu is followed by an electrolysis for refining, and since PGMs in crude copper have been industrially recovered from the resulting anode slime, our results indicated that Ag, Au, and Pd could be effectively recovered from MSW if the Cu-rich phase could be selectively collected.     

Are behavioral syndromes invariant? Spatiotemporal variation in shy/bold behavior in squid

Behavioral syndromes are correlated suites of behavior, analogous to human personality traits. Most work to date has been taken from limited “snapshots” in space and time, with the implicit assumption that a behavioral syndrome is an invariant property, fixed by evolutionary constraints or adaptations. However, directional selection on two mechanistically independent traits (selective covariance) could also result in correlated behaviors. Previously, we have shown that shy/bold behavior in Southern dumpling squid (Euprymna tasmanica) across predator encounter and feeding risk contexts is genetically and phenotypically uncoupled, and hence potentially free to vary independently. Here, we collected data on shy/bold behaviors from two independent wild populations of squid in two different years to test whether behavioral correlations across these same two functional contexts vary through time and space. We detected significant influences of population, sex, and body size on the expression of boldness in squid within each functional context, and this was coupled with significant differences in relative population density and adult sex ratio. Despite these changes in behavior and demographic parameters, we found that correlations between boldness scores across the two functional contexts were largely absent in both wild populations of squid in both years. Our work suggests that some animal groups may be largely characterized by context-specific behavioral expression. A theoretical framework which conceptualizes behavioral syndromes resulting from context-specific behavioral rules may be needed to fully understand why behaviors are sometimes correlated, and why sometimes they are not.     

南京市不同功能城区土壤中重金属Cu、Zn、Pb和Cd的污染特征

将南京城市建成区分为矿冶区、开发区、商业区、城市广场、风景区、老居民区等6大功能区,选择采集土壤样本56个,用原子吸收光谱仪选择分析了土壤中重金属元素的全量和活性形态含量.结果表明,南京城市土壤中Pb、Cu、Zn和Cd的总量分别为:117.1±103.7mg·kg^-1,39.86±39.9mg·kg^-1,273.3±131.6mg·kg^-1和1.13±0.7mg·kg^-1.矿冶区、老居民区、商业区、新开发区、城市广场和风景区的内梅罗重金属综合污染指数分别为:5.4、4.9、3.4、1.6、2.4和2.3.矿冶区以Pb、Cd的强度积累为特征,但活性形态的比重较小.而城市中心的居民区和商业区Zn的积累最显著,并且所测定的重金属的醋酸盐浸提态含量明显较高.除了风景区和城市市民广场外,城市中心区的重金属均表现出较明显的表聚性.城市活动区土壤Pb、Cd的强烈积累可能已经对人类健康构成了威胁.     

A systematic review of snake translocations to identify potential tactics for reducing postrelease effects

Advancements in the field of reintroduction biology are needed, but understanding of how to effectively conduct translocations, particularly with snakes, is lacking. We conducted a systematic review of snake translocation studies to identify potential tactics for reducing postrelease effects. We included studies on intentional, human-mediated, wild–wild, or captive–wild translocations to any location, regardless of motive or number of snakes translocated. Only studies that presented results for at least 1 of 4 outcomes (movement behavior, site fidelity, survival, or population establishment) were included. We systematically searched 4 databases for published studies and used 5 methods to search the gray literature. Our search and screening criteria yielded 121 data sources, representing 130 translocation cases. We quantified the association between 15 translocation tactics and short-term translocation outcomes by calculating odds ratios and used forest plots to display results. Snake translocations involved 47 species (from mainly 2 families), and most were motivated by research, were monitored for at least 6 months, occurred in North America, and took place from the 1990s onward. The odds of a positive snake translocation outcome were highest with release of captive reared or juvenile snakes, release of social groups together, delayed release, provision of environmental enrichment or social housing before release, or minimization of distance translocated. The odds of a positive outcome were lowest when snakes were released early in their active season. Our results do not demonstrate causation, but outcomes of snake translocation were associated with 8 tactics (4 of which were strongly correlated). In addition to targeted comparative studies, we recommend practitioners consider the possible influence of these tactics when planning snake translocations.     

Ownership property size,landscape structure,and spatial relationships in the Edwards Plateau of Texas (USA): landscape scale habitat management implications

The present research focused on using spatial analysis to determine relationships among land ownership property sizes and landscape structure, with a focus on conservation management implications. Indices and metrics of ownership property sizes and landscape structure were calculated for 20 km buffer areas around 31 North American Breeding Bird Survey transects, 12 located within the Edwards Plateau ecoregion and 18 in contiguous ecoregions. The number of bird species observed at each transect provided a measure of avian species richness associated with land cover classes for each respective transect (González in Urban influence on diversity of avifauna in the Edwards Plateau of Texas: effect of property sizes on rural landscape structure, Texas A&M University, 2005). Spatial correlations were calculated between each pair of the landscape indices. Spatial analysis identified a “threshold of habitat fragmentation” for the 500 acre (ac) ownership property size. Significant spatial correlations among variables showed that property sizes lower than 500 ac produced habitat fragmentation represented by a decrease in mean patch size (MN) and proximity among habitat patches (Index PROX). Spatial analysis also made possible the prioritization of ecological sub-regions of the Edwards Plateau for conservation or restoration. The Live Oak-Mesquite Savannah showed the highest average ownership property size (7305 ac) and the highest values of patch richness. Based on the results, management in the Live Oak-Mesquite Savannah sub-region should focus on the conservation of land mosaic diversity to assure native avian species turnover (Whittaker 1972). In Balcones Canyon Lands, 64 % of land was covered by farms smaller than 500 ac and the overall average ownership property size was above the threshold of fragmentation (1440 ac), implying that management policies there should focus both on habitat conservation and on restoration. In contrast, 71 % of land in the Lampasas Cut Plains was covered by farms smaller than 500 ac, and average ownership property size was very close to the fragmentation threshold (625 ac). Consequently, the results indicate that management in the Lampasas Cut Plains sub-region should focus on habitat restoration (e.g., corridors that connect isolated habitat patches). In general, the threshold of ownership property size, 500 ac, is important for conservation planning because below that threshold of property size, habitat patch size begins to decrease and the distance between equivalent patches of habitat increases. Isolated patches act as islands within a sea of less suitable habitat which produce negative effects on biodiversity. Identifying the spatial characteristics indicative of habitat fragmentation, or the likelihood thereof, is an important issue for conservation planning in places with urban sprawl influence.     

Heavy metal and trace elements in riparian vegetation and macrophytes associated with lacustrine systems in Northern Patagonia Andean Range

Vegetation associated with lacustrine systems in Northern Patagonia was studied for heavy metal and trace element contents, regarding their elemental contribution to these aquatic ecosystems. The research focused on native species and exotic vascular plant Salix spp. potential for absorbing heavy metals and trace elements. The native species studied were riparian Amomyrtus luma, Austrocedrus chilensis, Chusquea culeou, Desfontainia fulgens, Escallonia rubra, Gaultheria mucronata, Lomatia hirsuta, Luma apiculata, Maytenus boaria, Myrceugenia exsucca, Nothofagus antarctica, Nothofagus dombeyi, Schinus patagonicus, and Weinmannia trichosperma, and macrophytes Hydrocotyle chamaemorus, Isöetes chubutiana, Galium sp., Myriophyllum quitense, Nitella sp. (algae), Potamogeton linguatus, Ranunculus sp., and Schoenoplectus californicus. Fresh leaves were analyzed as well as leaves decomposing within the aquatic bodies, collected from lakes Futalaufquen and Rivadavia (Los Alerces National Park), and lakes Moreno and Nahuel Huapi (Nahuel Huapi National Park). The elements studied were heavy metals Ag, As, Cd, Hg, and U, major elements Ca, K, and Fe, and trace elements Ba, Br, Co, Cr, Cs, Hf, Na, Rb, Se, Sr, and Zn. Geochemical tracers La and Sm were also determined to evaluate contamination of the biological tissues by geological particulate (sediment, soil, dust) and to implement concentration corrections.     

Experimental study on soluble chemical transfer to surface runoff from soil

Environmental Science and Pollution Research - Prevention of chemical transfer from soil to surface runoff, under condition of irrigation and subsurface drainage, would improve surface water...     

Analysis and evaluation of chlorinated persistent organic compounds and PAHs in sludge in Korea

The concentrations of 12 POPs listed in the Stockholm convention, chlorophenols (CPs) and PAHs were investigated in sludge samples from wastewater and sewage treatment plants (WWTPs and STPs). The concentrations of PCDD/Fs in the wastewater sludge ranged from 0.189 to 1092 ng-TEQkg(-1) dry wt., and most of the sludge samples had levels below the EU guideline for the land application of PCDD/Fs (<100 ng-TEQkg(-1) dry wt.) except one sample. Co-PCB congeners were analyzed from four WWTPs, with total concentrations ranging from 0.265 to 26.6 ng-TEQkg(-1) dry wt., which were similar to the results obtained from previous studies. The levels of PCDD/Fs and Co-PCBs varied according to the main source of the influent to each WWTP and the paper industry was the main source of these compounds in the sludge due to the chlorine bleaching process. In case of OCPs, HCB and p,p'-DDE were detected at relatively high levels in the sludge samples compared to other target compounds, ranging from 1.30 to 21.5 microg kg(-1) dry wt. and 0.758 to 14.8 microg kg(-1) dry wt., respectively. Different OCP distribution patterns were observed according to sludge types, with HCB and DDTs being dominant in the sludge from WWTPs and STPs, respectively. The total levels of PAHs and CPs ranged from 1.24 to 44.9 mg kg(-1) dry wt. and 0.340 to 3.85 mg kg(-1) dry wt., respectively. The PAHs and CPs were also shown to have various distribution patterns, possibly due to the different wastewater sources to the WWTPs.